on-road track set-up tips.

[kryptonite5b]

so im not looking for all the answers as the "test and tune" is part of the fun, but whats a good starting point for my on-road gt-40/sportsline. im heading out to the track in july but just need a starting point for suspension and gearing. ive run my set-up in a dirty parking lot and it just doesn't feel right. all my cambers and casters are still from the factory and it looks like everything is still set at zero or whatever the factory settings are.
1) factory or zero caster and camber
2)50wt in the back and not sure bout the front
3)front and rear stabilizers
4)24/40-pinion and spur
5)red springs all around-2.8
6)eclipse #15's in the back and 20's up front.
the track looks like a large 8th scale road course. im running front disc brakes and fg pipe with high rpm clutch spring and a stock cy 23cc mill

 

[cyclops1970]

don't no if your interested in this but a local guy sinner_dee@hotmail has a fg onraod set gage for sale real cheap so you can log down your adjustments and no right where your at ? think it was 30 bucks

 

[cyclops1970]

http://forums.londonrc.com/showthread.php?t=21338

 

[Breathless]

I am interested.

Ernie

 

[breetie]

so im not looking for all the answers as the "test and tune" is part of the fun, but whats a good starting point for my on-road gt-40/sportsline. im heading out to the track in july but just need a starting point for suspension and gearing. ive run my set-up in a dirty parking lot and it just doesn't feel right. all my cambers and casters are still from the factory and it looks like everything is still set at zero or whatever the factory settings are.
1) factory or zero caster and camber
2)50wt in the back and not sure bout the front
3)front and rear stabilizers
4)24/40-pinion and spur
5)red springs all around-2.8
6)eclipse #15's in the back and 20's up front.
the track looks like a large 8th scale road course. im running front disc brakes and fg pipe with high rpm clutch spring and a stock cy 23cc mill

On a dusty, unprepared parking lot you'll find no manner of setup will allow your car to really shine. The dust is a major kicker in the ass of the setup wizzes, so a cleaned surface is usually the only option. Like 1/1 scale racing, the tires need to come to operating temp before it'll come into it's own, and even then, once you pick up some sand or dust or, worse, get up 'in the marbles' as they say, and it'll be a lap or two before it returns to normal.

My experience, admittedly, with 1/5 is still shaky, as I've only run in a couple events, and certainly nothing fantastic. However, I've been an experienced 1/10 and 1/8 scale racer for over a decade, so some things I was able to carry over. The biggest help, though, was actually my experience with 1/1 scale racing...

I usually start with a clean surface, if at all possible. While I won't sweep off an entire parking lot all by myself, I do carry a broom with me when I go parking lot bashing to sweep off any glaring spots that would clearly mess up my efforts. Normally I just head to my workplace, and the d00d there that handles facilities will hose off a section of the parking lot for me to use while I do my runs. Like I said, most of my most helpful experience actually comes from my experience in SCCA 1/1 scale stuff:

1). Clean road surface (at least major patches of dirt, sand, and dust)
2). A word on oil viscosities; general rules of thumb for shock oil is thicker oil for smoother tracks, thinner for rough. Finding the 'sweet-spot' is a tough one, and one I've never been able to master. However, the basic understanding of how shock valving works, and the job the oil does in dampening is key. For instance...most of us won't go through the trouble of re-valving our shocks to make adjustments, especially at the track. Instead, we buy extra shocks with different valving and matched viscosities of oil already assembled and ready to place on the car at a moment's notice. The important note, though, is to remember that in a typical situation, thick viscosity oil in a standard shock on a rough track will cause your suspension to 'float', which means you lose momentary contact with the road surface. Which means lost traction...the goal is to always try to make adjustments that will improve the contact of the tire to the road surface. Band-aids like using shock oil to change valving behavior is a half-successful effort at best, always try to use the right valving with the right oil. FG makes it easy, they only have a few valves to choose from, so it can make it simpler to have pre-assembled shock assemblies ready for testing.
3). Differential adjustment is much less obvious, in my opinion, and can make effecting changes a near science in scope. While some are in the habit of completely locking their diffs on rough tracks, I never recommend having a diff that does not bias at all. In my experience, adjusting a differential to work with the car in corners while providing true limited-slip in straightaways is a careful study of behavior, and knowing your machinery. You want the diff to give just enough to allow the outside tire to spin a bit faster than the inside tire in corners, yet provide adequate locking for near-even power delivery. This is critical when coming out of a corner. After the apex, just as throttle is coming up, so should your grip curve as power increases to the rear wheels. I don't have a true gauge for this, other than just seat-of-the-pants playing with it. Some are skilled enough to be able to look at tire wear in order to read how well a differential is doing its job. While I know some signs, I'm certainly no expert in that.
4). Spring rates front & rear are also pretty important. On average, the rule of thumb to follow here is stiffer in front, softer in the rear. Your mileage will most likely vary, however, because spring rates are specifically designed to work against the natural motion of your car to maintain attitude. You generally want stiffer in front for two reasons: one, on braking, centrifugal force throws the weight of your car forward, placing the front springs under orders of magnitude greater pressure than normal driving. You need to account for this to prevent the chassis from making contact with the road surface and to maintain attitude despite that momentary demand. Number two, the front is your pointing device; it provides you the means to change direction at speed. Those changes in direction also produce severe demand on the spring rate, so you need to have a stiff enough spring to handle those loads and still manage to keep reasonable contact of the tire to the road surface. In the rear, springs rates are softer because, one, there is less demanded of them, and two, softer spring rates encourage greater grip with a road surface. Tighter spring rates will increase bounce, thus reducing your tires' contact with the road. Too tight, and it can create resonance and even vibration, both sworn enemies of keeping tires in contact with pavement. However, adjustment is always necessary, the key is to have just enough. To find balance. Too much is as bad as not enough, and either can cost you pole positions.
5). Caster and camber are attitude adjusters; their purpose is to--like springs--work against the natural behavior of your car's chassis during cornering and acceleration. Negative camber is usually a first adjustment, as having negative camber allows the tires to provide a natural resistance to your car's tendency to lean or tip in corners, placing more emphasis on suspension tuning which allows the suspension more of an opportunity to work in concert with your camber adjustments to prevent chassis tip and sway, especially in corners. However...too much camber will result in poor straightaway performance, as that natural resistance works inward toward the chassis, making straightaway stability more difficult to maintain the more negative camber you have. As with shock and spring, your goal is balance, just enough...not too much or not enough. Caster is equally important, but means slightly different things going from front to rear. In the front, caster is applied to allow the tires to have extreme camber when rotated lock-to-lock. In this way, the tires have steadily increasing natural resistance against the car's tendency to dip, sway, or tip while making corners at speed. The more steering that is applied in any one direction, the more camber the front tires will have to work against the chassis. As always, you are making adjustments to the chassis to work against the laws of physics, to fight as much as is possible with the materials used to stave off centrifugal forces until that very last moment, just before the entire thing unravels and crashes you into a wall or another car. Hopefully, if you're set up right, that translates into faster laptimes. In the rear, caster plays a different role, known simply as 'anti-squat'. This is a delicate adjustment, as it mainly applies to initial power-on, and power coming out of corners. Anti-squat is as it sounds...caster applied to allow the rear suspension to work against the natural tendency of the chassis to 'squat' under power-on. Squat is bad in that it changes the telemetry of the rear tires in that instance that power is applied, the rear squats, and the camber angle of the rear tires is altered, just a bit. This natural behavior is why independent suspension systems do not make the best drag racing platform, because squat occurs, changing the camber angle of the rear tires and reducing the contact of the tire to the road. Since we're in road-racing here, the benefits of independent suspensions far outweighs any loss in contact of the tire to the road, but we do try to limit that change in attitude by increasing or decreasing caster in the rear. It's a real science, this, and not easily pointed at and such to say, 'oh, you need another quarter-degree of caster'. Maybe some can do that, I am not one of those. Your mileage will, no doubt, vary.
6). Tire compounds vary some, but the popular choices tend to win out, depending on the road surface they're applied to. The general rule of thumb, is softer tires for colder tracks, harder compounds for tracks that can heat up nicely. Now, this particular aspect can be debated endlessly, because some drivers merely determine tire compound to run solely on wear and longevity. Others feel that if a hard compound performs good on a hot track, that softer would perform that much better. However, proper application will show that indeed, you want softer compounds for colder conditions, to try and maintain the minimum grip levels your chassis is configured for, while harder compounds can be used based on temperatures reached once the cars are at speed. There are subtleties, however, in determining the right compound to use, and certainly the track surface plays a key role in this determination. For instance...I have seen pit crews for 1/1-scale race teams as well as 1/5 drivers choose to use soft compound tires on a hot track in order to help isolate the chassis more from rough track conditions. Harder compounds, while normally the appropriate choice for that particular track at that particular temp, are not ideal because the track surface is too rough for the harder compound to get warm and maintain traction. Similarly, then, you'll need to base your tire choices on the track itself, and how best to use your car's chassis setup to leverage the most grip and attitude. Again...a near-science. If not rocket science.

Anyway...just my thoughts. There's a lot more, but...this post just got real long. Sorry.